The invention relates to multimodality medical imaging systems for viewing anatomical structures and functions of a patient, such as combined x-ray Computed Tomography (CT) and Positron Emission Tomography (PET) scanners and, more particularly, to a patient handling assembly that reduces the overall length of the system.
Tomographic imaging devices or cameras are frequently used to assist in the diagnosis and treatment of a variety of anatomical structures and physiologic functions within the body of a subject patient, while minimizing the need for invasive procedures. Such devices typically utilize scanners that obtain data or information about such structures and functions from the patient at specified, discrete locations along the length of a patient. Using this information, the camera produces a series of images, each depicting a cross-section of the body of the patient, in a plane generally perpendicular to the length of the patient, and at specified points along the length of the patient. Combined, successive images or a substantially continuous spiral image taken along the length of a patient can yield a relatively three-dimensional view of internal organs and tissues, or at least provide a cross-sectional view of bodily structures or functions at various places on the patient. Tomographic cameras are most frequently used to view and treat organs and other tissues within the head, torso and trunk of a patient and, in particular, diagnose and treat such ailments as heart disease, arteriosclerosis, cancer, and the like.
Tomographic imaging cameras are often identified by the xe2x80x9cmodexe2x80x9d or xe2x80x9cmodalityxe2x80x9d of radiation used by their scanners to obtain patient data. Well-known scanner modalities include the X-ray Computed Tomography (CT), Magnetic Resonance Imaging (MRI), Ultrasound (ULT), Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) scanners. Camera systems which combine two or more different scanners to obtain a greater variety of imaging information from a patient are referred to as xe2x80x9cmultimodality imaging systems.xe2x80x9d Conversely, tomographic cameras utilizing the same mode to collect imaging information are referred to as having the same modality.
A tomographic camera utilizes a scanner having an array of radiation detectors forming a ring or bore that surrounds a patient. The scanner gathers information along a plane defined by the detector ring, which intersects the patient substantially perpendicularly to the length of the patient. Other processors and instruments coupled to the scanner form the tomographic image, based on information received from the scanner. To obtain information at successive points along the head, torso and trunk of a patient, the patient is supported horizontally on a patient table that translates or moves the patient horizontally through the bore of a tomographic camera.
It is often desirable to utilize two or more adjacent tomographic scanners of different modalities, in multimodality systems, to obtain a variety of imaging information from a single traverse of a patient through multiple scanner bores. This is highly desirable as a means of increasing efficiency (by completing two or more scans in one operation), increasing the accuracy of indexing, correlating or linking multimodality images to the same location along the length of the patient (by coordinating operation of the scanners to a single, controlled movement of the patient) and reducing the labor costs otherwise associated with separate, multimodality scanning operations.
In general, multimodality systems include a series of scanners, each having a different modality, supported by a single housing. Each scanner obtains different information about the patient, which, when registered in combination, provides a better understanding of the patient. More specifically, multimodality cameras typically include a scanner of anatomical structures of the patient (e.g., CT, MRI and Ultrasound cameras) and a scanner of physiologic functions of the patient (e.g., SPECT and PET cameras). The series of scanners forms a relatively long bore, typically longer than the combined head and torso of taller patients and spanning the entire length of shorter patients.
A patient table translates the patient through the scanners in a controlled manner, providing information to the system about the position of the patient. The position information it used to register the images formed from the scanner information to the same locations along the length of the patient. Unfortunately, conventional patient tables have a patient support surface that must be long enough to extend the patient from outside the first scanner bore, beyond the outlet of the final scanner bore. As a result, the patient support surface is typically longer than the entire length of the multimodality scanner assembly. Moreover, when the patient is positioned outside the scanner bores, at the front of the scanner assembly, the portion of the patient support surface extends forward from the assembly by a distance greater than the scanner assembly itself. This configuration is required particularly if the support surface is to be used to raise and lower the patient between the level of the scanner bores and the floor.
The combination of a lengthy multimodality scanner bore and longer patient support surface limit the facilities in which multimodality systems can be used, increase the cost of using and storing such systems and thus limit their availability. Accordingly, there is a need for a patient table for use in a multimodality tomographic imaging system that reduces the space required for use and associated costs.
The invention comprises a system and method for handling a patient in a tomographic imaging system using a plurality of imaging devices. The imaging devices each have a bore through which a patient is translated during scanning. One or more patient support structures extend from the front of the tomographic imaging system, where the patient is initially placed, through the bores of the system. The patient is translated through the bores of the system and along the patient support structures by an actuator.
In one aspect of the invention, a portion of the patient support structure extending from the front bore of the system is vertically adjustable, to position the patient in alignment with the scanner bores.
In another aspect of the invention, the patient is drawn through the scanner bores along the patient support structure by one or more belts.
In yet another aspect of the invention, the patient is supported on a pallet, which is drawn through the scanner.
In still another aspect of the invention, a portion of the patient support structure is positioned outside the bores at the front of the system, to vertically position the patient in alignment with the bores.